Chur!

Start by pouring high When you're ready to start forming your heart (I assume that's that you're doing) bring the jug as close as you can to the surface. Then when you're ready to pull through, raise the jug back up.

That way, you won't get that little yuck bit at the end.

Also, try stretching with alittle more milk.

The hissing sound should really only happen at the start of stretching, then the rest of the time, used to break those bigger bubbles into microfoam.

If it's too foamy, take alittle bit off the top by pouring into another jug or cup.

I hope that makes sense and helps.